Process for the manufacture of sulfid of zinc.



No. 823.896. PATENTED JUNE 19, 1906. G. HANSON.

PROCESS FOR THE MANUFACTURE OF SULPID 0F ZINC.

APPLICATION FILED APB.27.1904.

2 S ITS-SHEET 1.

No. 823,896. PATENTED JUNE 19, 1906. G. RANSON.

PROCESS FOR THE MANUFACTURE OF SULFID OF ZINC.

APPLICATION FILED APR.27.1904.

2 SHEETS-SHEET 2.

UNITED sra rns PA rnnir carton.

GEORGES HANSON, OF BRUSSELS, BELGIUM, ASSIGNOR TO EUGENE MARLlER, OF BRUSSELS, BELGIUM.

PROCESS FOR THE MANUFACTURE OF SULFIDOF ZINC.

Specification of Letters Patent.

Patented June 19, 1906.

Application filed April 27, 1904. Serial No. 205,234.

1'0 (tZZ 1071/0112, it may concern.-

Be it known that I, GEORGES RANSON, a citizen of the Republic of France, residing at Brussels, in the Kingdom of Belgium, have invented certain new and useful Improvements in the Process for the Manufacture of Sulfid of Zinc, of which the following is a specification.

Sultid of zinc as obtained by the various processes known at present has a thin character, is difficult to be reduced to a fine powder, and is of relatively small value for nu merous uses, such as, more particularly, painting, the vulcanization of caoutchouc, and other purposes.

Now this invention has for object to provide an improved process for the manufacture of sultid of zinc having a full or character, which is capable of being re uced to 'ti ve'ryfine powder, and is therefore specially suitable for numerous purposes, while also having an extremelysmnllll.cnsity.v The studies and investigations which have been made in connection with this process have led to the discovery that nascent hydrogen imparts new properties to hydrated sullid of zinc which differ considerably from those of the ordinary sullid of zinc existingin the trade.

N ow this invention consists, more particularly, in causing nascent hydrogen so to act upon sullid of zinc in the course of manufacture as to obtain the above-stated results. A convenient way of carrying the invention into effect consists in decomposing, according to a known reaction, a solution of sulfid of barium by means of zincate of barium with a view to obtaining sulf id of zinc and barium hydroxid according to the following reaction:

ZnO Ba. ms 211,0 ZnS entitoin In carrying out this operation zincato of ba riuin is formed by dissolving metallic zinc by means of barium hydroxid in the presence of sulfid of zinc in such a manner that the sultid of zinc which is formed by the decomposition of thesolutioirof zincatc by the sullid of barium shall in its product-ion be subjected to the action of the nascent hydrogen which liberated by the reaction of the barium hydroxid on the metallic zinc accord ing to the following reaction:

ilia(()l l. Zn i'io lia ill in order to enable the invention to be clearly understood, one way of carrying the same into effect will be described by way of example. It is known that if a concentrated solution of oxid of zinc and metallic zinc in barium hydroxid-that is to say, a solution of zincate of bariumbe added to a solution of sulfid of barium barium hydroxid and sulfid of zinc will be produced. Now, according to the present invention, with the obj cot of effecting the production of sulfid of zinc in the presence of nascent hydrogen, the formation of the zincate of barium is effected actually in the presence of the suliid of zinc. For this purpose metallic zinc, barium hydroxid, and water, preferably in the following proportions: three hundred parts, by weight, of zinc to about two hundred parts, by weight, of crystallized barium hydroxid (Ba (0H),, H 0) and four hundred parts of water, are introduced into any suitable apparatus made of metalfor example, ironcapable of being hermetically closed and provided with a charging-orifice and with a dischargingorifice connected to a steam-heater, with an escape-pipe and a pipe for the supply of sulfid of barium or sulfid of another earthy alkali.

The apparatus having been charged with the above-stated proportions of zinc, crystallized barium hydrate, and water, the tem perature is gradually raised to about 100, so as to dissolve the barium hydroxid. The latter is converted at once into zincate of barium, with evolution of hydrogen. The re action reaches its maximum intensity at the temperature of 100 centigrade. The eilervescenee diminishes as soon as the barium hydroxid has dissolved about forty-seven one-hundredths of the weight of zinc, which it is theoretically cap able of dissolving. The dissolution is the more rapid the greater the surface of the zinc. It requires about ten minutes with the proportional quantities above mentioned, assuming a surface of zinc of about one square meter for every four kilo-. grams of zinc. The hydrogen which is evolved during the reaction remains the hmmetimilly-closed. apparatus-for the purpose of lmingreeovcred.t. This action is preliminary. The hydrogen evolved at this stage of the process takes no part in the latter reaction. As soon as the proportion of the zinc dissolved by the barium hydroxid has attained about the quantity above stated-that is to say, forty-seven one-hun- ICO dredths of the uantity of zinc which is capable of being dissolved by the barium hydroxid present-thcre are introduced into the apparatus about thirty parts, by weight, of a solution of suliid of barium of a strength of about two hundred and thirty grams of sulfid (B as) per liter. After this h as been converted into hydrated barium the concentration of the mass in the apparatus will be at the degree of about four hundred and thirty grams of hydrated barium hydroxid' (Ba(O1I) +8H- O) per liter.

The above-stated proportion of sulfid of barium must be observed within certain limits in order to obtain good results from the operation, and in any case the quantity of sulfid of barium which is introduced into the apparatus should always be less than that which is required to convert into barium hydroxid the total quantity of zincate due to the quantity of the dissolved Zinc. Under these conditions the sulfid of barium is completely decomposed as soon as it is introduced into the apparatus and is converted into barium hydroxid without any interference with the dissolving of the zinc. In cases where this proportion is not observedthat is to say, where sulfid of barium is introduced in excess into the apparatusa formation of sulfid of zinc upon the zinc will take place and by isolating the latter will consequently considerably slacken the rate of formation of the zincate of barium.

The prescribed conditions having been observed, a precipitation of sulfid of zinc takes place with the formation of barium hydroxid by the decomposition of a corresponding quantity of zincate. The operation which has thus been begun may be eflected on a large scale in a continuous manner by insuring that the substances are caused to act upon one another approximately in the proportions above indicated. The zincate of barium, which is necessary for the decomposition of the solution of sulfid of barium, is formed in consequence and, contrary to the known processes, continuously by the dissolving of the metallic zinc. The hydrogen which is thus being continuously evolved acts in its nascent state upon the resulting sulfid of zinc and imparts to it the new properties above stated. This evolution of hydrogen is further promoted by the use of the iron appara-tus above mentioned, which forms a voltaic couple with the metallic zinc; but in proceeding in this manner it will be found that the reactions soon diminish considerably in intensity and that if the operation be carried on beyond a certain length of time it will be found that the sul'lid of zinc thus obtained is rendered impure by a certain quantity of suliid of iron. This drawback is due. to the fact that during the reaction there produced. upon the iron of the apparatus an adhering coating of; sullid of iron which isolates the metal and which is formed with a rapidity that is much greater when solutions of sullid of barium are employed which are rich in polysuliids. The layer of sul'lid of iron thus formed soon becomes detached in the form of small particles, which constitute an impurity in the sulfid of zinc so produced. This disadvantage may be avoided by employing an apparatus composed of stoneware or of iron coated with a suitable enamel or with any other substance which is not alfected by the products of the reaction; but in such cases the course of the operations is particularly slow by reason of the absence of the beneficial action due to the presence of the voltaiccouple zinc-iron, which promotes the course of the reaction and the evolution of the hydrogen. With the object of retaining this advantage, while avoiding the occurrence of impurity in the sulfid of zinc, the operations are preferably .carriedout, in an apparatus whichis composed of a neutral material as re g r he. ,pr ..d1 9 .QL.tlienteaa iall. and, 1 i'Yl iflli metal u copp e rin a suitable state of subdivision introduced in such quantity as to produce an energetic voltaic couple with the zinc that is required in the reaction. The said metal is arranged in such a manner as to be capable of being rapidly and easily removed from the apparatus and replaced therein by a fresh quantity of new metal as soon as it has become covered with such a quantity of suliid as will produce a slackening of the reaction. By this means the manufacture can be rendered very uniform, and an almost constant energy of reaction may be maintained, and the presence of sulfid of iron in the sulfid of zinc so obtained may be completely avoided, while the production of hydrogen is promoted by offering constantly fresh metal .to the reaction.

The metal introduced forthe purpose oi promoting the reaction may be in the form of perforated plates or baskets of enameled iron wire in which are arranged layers of zinc alternating with layers of clippings, cuttings, shavings, &c. of iron or copper. One or more of such baskets are placed in the apparatus, which is of stoneware or enameled metal and are kept therein up to the moment when the intensity of the reaction commences to slacken. At that moment the basket or baskets or plates are removed and are replaced by fresh baskets or plates charged with fresh metal.

The greasy nature and the degree of "lineness of the sulfid of zinc is found to vary according to the intensity of the reaction. The sul'lid of zinc produced as described in the presence of nascent hydrogen can be readily dried and will fall to powder as soon as the moisture which has :aused it to cohere together has been eliminated therefrom by the action of heat.

such as, for instance, iron or The process hcreinbcfore described may be carried into practice by aid of the apparatus shown in the annexed drawings, in which- Figure 1 is a side view, partly in section, of the Whole apparatus. Fig. 2 is a detail view of one of the baskets of enameled iron wire above referred to and the frame carrying the said baskets, and Fig. 3 is a section through one of the baskets.

Referring to Fig. 1, a, is a vessel in which zinc, crystallized barium hydrate, and water are charged in the above-given proportions. The charging-orifice b of the said vessel may be hermetically closed by a cover 0, and (Z is a discharging-orifice, and e an outlet-pipe.

f represents suitable gage-cocks, and g is a steam-heater connected to a boiler. (Not shown.)

In the vessel a is placed on suitable supports 9 a frame 7:. (Shown more particularly in Fig. 2.) One of the vertical bars i of the said frame is adapted to be rocked on a pivot j, so as to allow a number of baskets is of enamel iron wire, in which are arranged the layers of zinc Z, Fig. 3, alternating with the layers m of clippings, cuttings, shavings, or the like, of iron or copper, to be placed within the frame it on supporting-rods a. Theframe It may be readily placed into the vessel 0 or removed thereform by aid of a suitable apparatus 0 when the cover 0 is removed from the vessel a. p is a suitable vessel containing the solution of sulfid of barium. The said vessel is provided with a chargingpipe q, fitted with a cock 1', and with two pipes s t, provided with cocks a '0. The pipe 3 is adapted to discharge the solution of sulfid of barium into the vessel (1- when the cock u is open. The pipe t with cock 1) has for its purpose to obtain the same pressure in both the vessels a and p. Y

w is a pipe adapted to conduct the hydrogen evolved in the vessel a to gas-purifying apparatuses a: of well-known construction and therefrom into a suitable gasometer y,

where the said gas is recovered.

The operation of the apparatus will be ob vious from the explanations given with the preceding description.

\Vhat I claim is 1. The process consisting in decomposing a solution of sul'lid of barium by means of zincate of barium, the said zincate of barium being formed by dissolving metallic zinc by means of barium hydroxid in the presence of the suli'id of zinc produced so as to subject the said sulfid of zinc to the action of the nascent hydrogen liberated by the reaction of the barium hydroxidon the metallic zinc substantially as and for the purpose described.

2. The process which consists in first heating metallic Zinc, crystallized barium hydroxid and water so as to dissolve the barium hydroxid and convert it into zincate of barium with evolution of hydrogen, then introducing a solution of sulfid of barium and finally decomposing said solution by means of the zincate of barium and in the presence of the nascent hydrogen liberated by the reaction of the barium hydroxid on the metallic zinc substantially as and for the purpose described.

3. The process which consists in first heatingmetallic zinc, crystallized barium hydrate and water, so as to dissolve the barium hydroxid and convert it into zincate of barium with evolution of hydrogen, then introducing a solution of sulfid of barium of a strength of about two hundred and thirty grams of sulfid per liter, as soon as the quantity of the zinc dissolved by the barium hydroxid has at tained about forty-seven one-hundredths of the quantity of zinc which is capable of being dissolved by the barium hydroxid present and then finally decomposing the said solution of sulfid of barium by means of the zineate of barium and in the presence of the nascent hyd o en liberatedby the reaction of the barium Esteem" on the metallic zinc so as to obtain a precipitation of sulfid of zinc which takes place sinulltaneously with the formation of barium hydrate, substantially as and for the purpose described.

In witness whereof I have hereunto set my hand in presence of two witnesses.

GEORGES HANSON. Witnesses:

MAURIoE GERBEAULT, GREGORY PIIELAN. 

